1) Field of the Invention
This invention relates generally to mining machines and, more particularly, to mining machines adapted to bore into relatively low coal seams.
2) Description of the Prior Art
Generally, two types of mining procedures are used to extract coal from coal seams, underground mining and above ground mining. In either case, the coal seam is usually sandwiched between layers of rock. In the case of underground mining, various methods can be used to extract the coal, such as explosives or long wall and short wall mining apparatuses, that are well known in the art. Above ground coal extractions can be accomplished through the use of large cranes or other types of extraction devices, which are also well known in the art.
Generally speaking, the higher the coal seam, the more profitably it can be extracted. In many areas throughout the United States, the higher coal seams have been extensively mined. However, many of the lower coal seams remain intact because it was not economically feasible to mine them. By "low coal seam", it is meant coal seams which are approximately thirty inches thick or less. Devices using the present gear reduction technology cannot effectively and efficiently mine these seams. Therefore, it is an object of my invention to profitably extract coal from low coal seams.
Further, in many instances, coal extracted from low coal seams under the present technology includes substantial quantities of rock. The extracted coal must then be cleaned and prepared. The more rock and other non-coal products found in the extracted coal, the more the coal must be processed. This results in substantial amounts of waste water and tailings and has a negative impact on the environment, as well as the yield, which directly affects the profitability of the coal mining operation. Present continuous mining excessive amounts of "fines" (small particles of coal), which negatively affects the price of the mined coal. Therefore, it is also an object of my invention to extract coal having a minimal impact on the environment and maximum profit.